Probably a resistive short similar to usual load.
73
vk4tux
On Wed, 5 Nov 2025, 9:54 am Alek Petkovic via groups.io, <vk6apk=
bigpond.com@groups.io> wrote:
> With the way you describe the symptoms, I can't begin to work out what is
> happening.
>
> When you pull the failed relay, have you ever tested it out of circuit?
> That is, powered it and measured with an ohm meter to see if the contacts
> are moving to verify if it is a coil or contact problem.
>
> Do you have speed up circuits (high volts and series resistor) in your
> amps?
>
> Have you smashed or cut one open to see what has failed?
>
> I'm at a loss but I'll follow the thread with great interest.
>
> Cheers, Alek VK6APK.
> On 5/11/2025 7:17 am, Tim Duffy K3LR wrote:
>
> A few times in the past 30 years the output relay of my single band
> amplifiers have failed.
>
> They are used pulls – HC1 and RJ1. Typically from MGS.
>
> I am not upset that they fail – they have a finite life, but my question
> is – how they fail.
>
>
>
> RF output goes to zero – and the meters (plate and grid) continue to look
> normal. That is just strange to me.
>
>
>
> When the output relay fails – why doesn’t the amplifier go nuts – drawing
> excessive current, etc.?
>
>
>
> I always have 25 mS of TX delay – so the RF is never “hot switched”.
>
>
>
> 73
>
> Tim K3LR
>
> _._,_._,_
> ------------------------------
> Groups.io Links:
>
> You receive all messages sent to this group.
>
> View/Reply Online (#41606)
> <https://groups.io/g/ham-amplifiers/message/41606> | Reply to Group
> <ham-amplifiers@groups.io?subject=Re:%20Re%3A%20%5Bham-amplifiers%5D%20Vacuum%20relay%20question>
> | Reply to Sender
> <vk6apk@bigpond.com?subject=Private:%20Re:%20Re%3A%20%5Bham-amplifiers%5D%20Vacuum%20relay%20question>
> | Mute This Topic <https://groups.io/mt/116126674/1015776> | New Topic
> <https://groups.io/g/ham-amplifiers/post>
> Your Subscription <https://groups.io/g/ham-amplifiers/editsub/1015776> |
> Contact
> Group Owner <ham-amplifiers+owner@groups.io> | Unsubscribe
> <https://groups.io/g/ham-amplifiers/leave/14320638/1015776/1929309408/xyzzy>
> [vk4tux@gmail.com]
> _._,_._,_
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|